I heard there is a substitute for Cordarone. Less effective but fewer side effects? Can anyone tell me if this chemistry works well enough to switch? (Dronedarone)

I developed AIT and was really ill for 18 months with an overactive thyroid my heart was mimicking the thyroid and would go Afib flutter and then stop, luckily I have an ICD implant, One Cardiologist wanted to stop the dose and the other wanted to keep me on the Cordarone I finished up staying on the drug, like I say it took 18 months for the thyroid to settle and I finished up on Steroids and Neomarcazole, Is there a better way of treating AIT? I worry that the AIT will return.